/*
 * Copyright (c) Kumo Inc. and affiliates.
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <melon/portability.h>
#include <melon/lang/hint.h>

namespace melon {
    /**
     * Call doNotOptimizeAway(var) to ensure that var will be computed even
     * post-optimization.  Use it for variables that are computed during
     * benchmarking but otherwise are useless. The compiler tends to do a
     * good job at eliminating unused variables, and this function fools it
     * into thinking var is in fact needed.
     *
     * Call makeUnpredictable(var) when you don't want the optimizer to use
     * its knowledge of var to shape the following code.  This is useful
     * when constant propagation or power reduction is possible during your
     * benchmark but not in real use cases.
     */

    template<class T>
    MELON_ALWAYS_INLINE void doNotOptimizeAway(const T &datum) {
        compiler_must_not_elide(datum);
    }

    template<typename T>
    MELON_ALWAYS_INLINE void makeUnpredictable(T &datum) {
        compiler_must_not_predict(datum);
    }
} // namespace melon
